(b 1) Field of the Invention
This invention relates to a method of optimizing the thickness of a layer of resist in order to minimize or eliminate the side lobe effect, and more particularly to selecting the thickness of a layer of resist corresponding to a relative maximum of the curve of reflectivity as a function of resist thickness.
(2) Description of the Related Art
This invention describes a resist process to adjust the thickness of the resist layer to minimize or eliminate side lobe effect by choosing the resist thickness resulting in the lowest light intensity at the resist surface.
U.S. Pat. No. 5,354,632 to Dao et al. describes a phase shifting reticle having at least one first, second, and third areas. The transmittance of the second area is less than the transmittance of the first area. The second area provides a 180.degree. phase shift. The third area is substantially opaque.
U.S. Pat. No. 5,633,713 to Tanaka et al. describes a system and method for measuring the distribution of absorption light amount in photoresist.
U.S. Pat. No. 5,556,726 to Yuan describes a method to determine exposure dosage without knowledge of underlying film thickness and refractive index and handle either resist thickness change or underlying film thickness/refractive index change or both.
U.S. Pat. No. 4,977,330 to Batchelder et al. describes an in-line photoresist thickness measuring device.